Improvement in hot-air furnaces



-UNITED STATES PATENT 'oi-Fica WILLIAMII. Lofrz, OF CHICAGO, ILLINOIS.

4IMPracviawnaur IN Hor-Am FuRNAcEs.

Specification forming p art of Letters Patent No. 177,S5`7,.dated May23,1876; application `filed July 9, 187,5.

August 11, 1874;and on October 27 1874, for

animprovement thereon; and has for its ob- Ject to secure a more perfectcombustion of the gases, through the means more fully7 hereinafter setforth and claimed.

Figure' 1, Sheet l, isv a perspective view of my improved portablefurnace. Fig. 2 is a vertical section at a: m. Fig. 3, Sheet 2, is ahorizontal section at y y in Fig. 2. Fig. 4 is a similar section at z zin the same figure.

In the drawing, A represents the ash-pit, having a circular opening inits top plate, in which is hung a grate, B. A lire-pot, C, rests uponthe ash-pit, and incloses the grate-opening. The back part of thefire-pot is higher than the front, and is covered by a fiat plate, a,whose shape is that of an irregular segment, in front of which there isa combustionchamber, G', into the lower front part of which `is carriedan inclined fuel-chute, D, whose lower wall forms a prolongation of thefront of the fire-pot. The upper end of the chute extends through thecasing J, and is provided with a fuel-door. Between the inner edgeof theplatea and the back wall of the combustion-ch amber there isa pendenthollow bridgevwall, b, extending transversely across thecombustion-chamber, with'a narrow slit, c, along its lower edge for thedelivery of air, which is carried to it by a bent pipe, d,ex

l tending up the back and over the top of the combustion-chamber, andthrough the casin g, the volume of air admitted being regulated by aregister, c. From the plate athree iiues, E, rise into a horizontalhue-chamber, F, connected at the front by a passage, F', with an outerannular flue-chamber, G, at one side of which there is an exit-flue, K,carried out through the casing to a smoke-pipe, K'. G' is a segmentalHue-chamber, which nearly surrounds the ash-pit. rlhe annular flue G isdivided into two parts by a partition, j', at the back. Access is had tothe front part bya door, at one side of which is a revertibledraftdamper, g, which closes the said 'fine to the passage of theV gasesof combustion to the exit-flue, in which case they are compelled to passinto the left side of said flue G, thence down into the segment G',through six dropl fines, H; thence up through six ascending lines, H',to the right side of the flue G before finding an exit therefrom. Accessis had to the flue G' through doors and passages through the casing, toremove accumulations of dust deposited therein. I is an annularevaporating-pan, supported by short legs :above the annular flue G. J isthe casing of the furnace, and K2 are the hot-air flues issuing from itstop.

The fuel-chute is inclined at the angle at which coal will fall from apile, and serves as a magazine, in which the fuel is coked and caused toyield up its gases, which naturally rise and expand into the largecombustionchamber C', at the top of which there is a register, h, foradmitting atmospheric air to mingle with them in the proper proportionto prepare them for ignition. The draft of the furnace is at the backpart ofthe fire-pot, owing to the lesser depth of coal there, and themixed air and gases are drawn back runder the bridge-wall, where a thinstream of highlyheated air niingles with them at the proper temperatureto ignite them, the ignition being secured by their passing over theincandescent fuel, in close proximity to its upper surface, so thatclear flame alone will be found back of the bridge-wall, proof of whichis found in the fact that 'bituminous coals 'of the poorest quality havebeen continuously consumed in such furnaces without giving off smoke.

What I claim as my invention is- 1. In an air-heating furnace, and incombination, the hollow bridge-wall across the back part of thefire-pot, and within the same, and having a narrow slit across'its lowerend, and an air-tube, having a register at its outer end, said tubepassing over and behind the combustion-chamber, and its inner endterminating directly over the slit aforesaid, substantially as and forthe purposes set forth.

2. In an air-heating furnace, the combination of the following elements,viz :l a fire-pot, havingan elevated combustion-chamber di rectly aboveand connected with it, and closed at the top; al1 inclinedmagazine-chute, adapted to deliver fuel to the front of the fire-pot; ahollow transverse bridge-wall, adapted to deliver a thin stream of hotair into the fire-pot back of the inner mouth of the magazinechute; atube with a register for admitting hot air to the gases of combustionbefore passing under the' bridge-Wall; and ues at the back of therepotfor carrying off the products of combustion, substantially Vasdescribed.

3. In an airheating furnace, the combination of the annular flue G,having the partition f and revertible damper g, the segmentl ue G', thediving and ascending ues H H', and the iues E, F, and F', and thefire-pot G, substantially as and for the purposes set forth.

4. In an air-heating furnace, in combination, the pendent bridge- Wallwithin the tire-pot v and across the same, the combustion-chamber,

and the eduction-ii'ues, for the. purpose of interposing saidbridge-wall and the current of hot air passing through it between theopening into the combustion chamber and the opening into rtheeduction-iues, substantiallyl as described and shown.

' WILLIAM El. LOTZ.

Witnesses GEO. FROMMANN, CARL MEYER.

